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EP1683626A1 - Procédé et dispositif de traitement d'un article moulé par injection avec un gaz - Google Patents

Procédé et dispositif de traitement d'un article moulé par injection avec un gaz Download PDF

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Publication number
EP1683626A1
EP1683626A1 EP05001442A EP05001442A EP1683626A1 EP 1683626 A1 EP1683626 A1 EP 1683626A1 EP 05001442 A EP05001442 A EP 05001442A EP 05001442 A EP05001442 A EP 05001442A EP 1683626 A1 EP1683626 A1 EP 1683626A1
Authority
EP
European Patent Office
Prior art keywords
mould half
polymer
gas
closed space
polymeric article
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP05001442A
Other languages
German (de)
English (en)
Inventor
Joachim KARTHÄUSER
Anders Marcusson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Linde GmbH
Original Assignee
Linde GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Linde GmbH filed Critical Linde GmbH
Priority to EP05001442A priority Critical patent/EP1683626A1/fr
Priority to PCT/EP2006/000458 priority patent/WO2006079477A1/fr
Publication of EP1683626A1 publication Critical patent/EP1683626A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/0053—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor combined with a final operation, e.g. shaping
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C71/00—After-treatment of articles without altering their shape; Apparatus therefor
    • B29C71/009—After-treatment of articles without altering their shape; Apparatus therefor using gases without chemical reaction
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/03—Injection moulding apparatus
    • B29C45/04—Injection moulding apparatus using movable moulds or mould halves
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2083/00—Use of polymers having silicon, with or without sulfur, nitrogen, oxygen, or carbon only, in the main chain, as moulding material
    • B29K2083/005—LSR, i.e. liquid silicone rubbers, or derivatives thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2011/00—Optical elements, e.g. lenses, prisms
    • B29L2011/0016—Lenses
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2011/00—Optical elements, e.g. lenses, prisms
    • B29L2011/0016—Lenses
    • B29L2011/0041—Contact lenses
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00—Other particular articles
    • B29L2031/30—Vehicles, e.g. ships or aircraft, or body parts thereof

Definitions

  • the invention relates to a method for the production of a polymeric article in a moulding tool comprising a first and a second mould half, wherein a liquid polymer is introduced into a cavity between said first and said second mould half, said polymer is at least partly solidified, and said at least partly solidified polymer is subjected to a gas treatment. Further, the invention relates to an apparatus for the production of a polymeric article, comprising a moulding tool with a first and a second mould half.
  • a liquid polymer is filled into a mould cavity, cooled down and solidified in order to obtain a polymeric article having the same shape as the mould cavity.
  • Such moulding processes are carried out with or without the application of pressure.
  • a silicone contact lense is desired to be hydrophilic
  • an automotive head light should be scratch-resistant
  • a catheter should have a low-friction surface and so forth.
  • the treatment of the polymeric articles in separate reactors requires special hardware and additional handling which increases the process time. Further, it includes the risk of contamination of the polymeric articles during transport and handling. In some cases, the polymeric articles may be very small and difficult to handle, for example contact lenses. In other cases the post-treatment, e.g. the application of a scratch-resistant coating may require a long process time, in yet other cases the binding or adhesion between the polymeric article and a coating may be unsufficient.
  • a method should be provided which is suitable for the surface or bulk treatment of polymeric articles while the articles are still in the moulding tool.
  • a method for the production of a polymeric article in a moulding tool comprising a first and a second mould half, wherein a liquid polymer is introduced into a cavity between said first and said second mould half, said polymer is at least partly solidified, and said at least partly solidified polymer is subjected to a gas treatment, wherein after said polymer is at least partly solidified said second mould half is removed, a cover is placed onto said first mould half, a closed space is formed between said cover, said polymer and / or said first mould half, and said gas is introduced into said closed space.
  • a polymeric article is chemically or physically modified directly after its production.
  • the polymeric article is moulded in a moulding tool comprising a first and a second mould half using conventional moulding technology.
  • a liquid polymer is introduced into a cavity between said first and said second mould half and sufficiently solidified. Solidification can occur via reduction of temperature until at least partial crystallization occurs, or via chemical crosslinking.
  • At least partly solidified means that the polymeric article is mechanically stable without the support from the second mould half.
  • thermoplastic this means that the temperature of the article has decreased to 5°C below the glass transition point of the polymer.
  • cross-linking silicone this can be related to a 95% cross-linking degree.
  • the moulding process can be carried out with or without the application of pressure.
  • silicone contact lenses are moulded under slightly elevated pressure whilst thermoplastic articles especially in multi-cavity tools are held under high pressure, equivalent to tons of holding power.
  • the moulding tool is opened and the second mould half is removed from the at least partly solidified polymeric article, so that the surface of the polymeric article which has initially been in direct contact with the second mould half does no more touch the corresponding surface of said second mould half. Thereby the polymeric article remains in the first mould half.
  • a cover is placed onto the first mould half such that a closed space is formed between said cover and the at least partly solidified polymeric article or between the cover and the first mould half or between the cover, the first mould half and the polymeric article.
  • the cover is not typically meant to touch the polymeric article. It is possible that the cover has partly contact with the polymeric article, but preferably the cover and the polymeric article do not touch each other at all.
  • the main purpose of the cover is to keep a gas for a period of time in that closed space adjacent to the polymer.
  • said cover comprises a ring-like device and said second mould half. That means a ring-like device is inserted between said first and said second mould half. In this way a closed space is created between the surface of the polymeric article, said ring-like device and said second mould half.
  • ring-like device means any device which may be placed between the first and the second mould half so that a closed space is formed by said two mould halves and said ring-like device.
  • an apparatus for the production of a polymeric article comprising a moulding tool with a first and a second mould half, further comprises a ring-like device with at least one gas inlet and optionally at least one gas outlet, wherein said ring-like device is insertable between said first and said second mould half defining a closed space between said first mould half, said ring-like device and said second mould half.
  • the ring-like device may be integrated into the second mould half, e.g. by retractable elements within the second mould half, however, a separate device will typically be the more economic solution.
  • the ring-like device does preferably not touch the polymeric article located in the first mould half.
  • the main function of the ring-like device is to keep the dense phase gas for a period of time in that closed space between the polymer and the second mould half.
  • the ring-like device is not intended to modify the shape of the polymeric article according to the shape of the ring-like device.
  • the ring-like device It is advantageous to provide the ring-like device with a gas inlet in order to supply the gas, and if desired suitable additives, to the closed space. It is also possible to provide the ring-like device with separate inlets for additives, such as polymer precursors, metal salts, or other chemicals.
  • a gas especially a compressed gas or a dense phase gas, is supplied into the closed space, and the polymeric article will be impregnated by that gas.
  • the pressure in the closed space is reduced, the tool is opened and the impregnated and finished polymeric article is removed.
  • a compressed gas and more preferred a dense phase gas is introduced into said closed space. Due to its good solubility characteristics preferably carbon dioxide with or without additives is used.
  • additives which may be introduced into the closed space together with said gas are for example polymer precursors, metal salts, dyes or other suitable chemicals.
  • the process is carried out on multi-stage injection moulding machines.
  • the polymeric article is produced in a multi-stage process in different stations, wherein between two stages said polymer is transferred from one station to another, and wherein said polymer is subjected to said gas at least at the second station, but optionally at both stations.
  • the production process comprises one moulding station and two impregnation stations where the polymeric article is subjected to the inventive gas treatment step.
  • a liquid polymer is filled into the moulding tool and the polymeric article is formed. After at least partly solidifying the polymer, the polymeric article is transferred from the moulding station to the first impregnation station.
  • the moulding station it is then possible to produce the next polymeric article while the prior produced polymeric article is impregnated in the first impregnation station.
  • the partly impregnated polymeric article is transferred to the second impregnation station for final impregnation, the polymeric article just formed in the moulding station is moved to the first impregnation station and the moulding tool may be filled with liquid polymer again.
  • the transfer between different stations in a multi-stage production process may be carried out by a a rotatable tool or a conveyor belt.
  • advantages in cycle time are achieved.
  • Multiple or consecutive impregnation can be achieved by rotating the tool three times 90° and performing the impregnation three times at the positions 90°, 180° and 270°, or up to a total of seven times at the positions 0° (once directly after moulding), 90° (twice), 180° (twice) and 270° (twice).
  • the invention is in particular useful for producing silicone-based articles or polymethacrylate or polycarbonate articles, as specific examples for rubbers and thermoplastics. It is also possible to add certain substances, for example silanes, during or after the moulding of glassware and porcelain. Further, in a metal-injection-moulding process the invention can be used for subsequent surface treatment or removal of sacrificial binding agent.
  • the inventive method is especially advantageous in cases where the polymeric articles cannot be impregnated once they are cooled down.
  • the polymeric article typically has a temperature of between 100 and 200 °C, and the diffusion coefficients, and therefore the efficiency for gas-assisted impregnation, is significantly higher at these elevated temperatures.
  • the inventive method uses the residual heat available in both the polymeric article and the e.g. electrically heated, moulding tool. In specific cases the heat is gradually removed from the polymeric article during the gas assisted impregnation, thereby reducing the risk of mechanical deformation. In that respect, the gas impregnation serves also as a controlled cooling method.
  • the inventive method may be used for the production of an automotive headlight by injection moulding.
  • a moulding tool comprising a first 1 and a second moulding half 2 is closed (figure 1) and a liquid polymer 5 is injected into the mould cavity 3 through a polymer inlet 4 in order to form a polymeric article 6 (figure 2).
  • the moulding tool is opened by removing the second mould half 2 (figure 3).
  • the polymeric article 6 is not yet cooled down to ambient temperature, but has a temperature of preferably between 100°C and 200°C.
  • a ring-like device 7 is placed between the first mould half 1 and the second mould half 2 (figure 4), and the moulding tool is closed again (figure 5).
  • a closed space 8 is generated between the polymeric article 6, the ring-like device 7 and the mould halves 1, 2.
  • Carbon dioxide at a pressure of 100 bars, together with suitable additives such as acrylates, is injected into the closed space 8.
  • the carbon dioxide and the additives diffuse into the polymeric article and cause a chemical and / or physical modification of the characteristics of the polymeric article, in particular of its surface properties.
  • the moulding tool is opened and the polymeric article is removed (figure 6).
  • the article may be exposed to UV light to initiate the polymerization of additives now deposited into the thermoplastic.
  • Silicone such as 2-component LSR
  • the mould is brought to elevated temperature for a sufficient time to cross-link the silicone monomers, e.g. 20 min at 70 °C.
  • the mould is opened, and a ring-like metallic device is positioned between the moulds.
  • the moulds are closed and held with sufficient pressure to enable filling the closed space with compressed gas.
  • the closed space is herein defined by the moulds, the ring-like device and the contact lense.
  • the gas preferably used is carbon dioxide along with additives such as selected from the group of compounds mentioned in WO 03/068846 A1, and / or specifically selected from the group of compounds containing vinyl groups, such as vinylpyrrolidone, and mono- and bis-acrylates and -methacrylates, such as 2-hydroxy-ethyl-methacrylate (HEMA), or triethylene glycol di(meth)acrylate, or other hydrophilic acrylates and methacrylates.
  • additives such as selected from the group of compounds mentioned in WO 03/068846 A1, and / or specifically selected from the group of compounds containing vinyl groups, such as vinylpyrrolidone, and mono- and bis-acrylates and -methacrylates, such as 2-hydroxy-ethyl-methacrylate (HEMA), or triethylene glycol di(meth)acrylate, or other hydrophilic acrylates and methacrylates.
  • Polymerisation of the monomers e:g. the acrylate monomers impregnated into the silicone matrix, is preferably achieved by UV light, and preferably by exposing the impregnated article to UV light while the article is held under pressure, e.g. through a window in the second mould half.
  • the invention may also be used to colour mobile phone display windows made of PMMA.
  • PMMA is injection moulded and subsequently treated similar to the items in example 1.
  • the gas (CO 2 ) injected into the closed space contains CO 2 -soluble pigments such as phtalocyanine dyes.
  • polycarbonate articles e.g. automotive or telecom parts
  • polycarbonate articles e.g. automotive or telecom parts
  • compounds selected from the group of derivatives of acrylic and methacrylic acid e.g. esters, glycols, silanes
  • group of derivatives of styrene polystyrene of mol weight between 300 and 10 000, and grafted derivatives thereof
  • the group of glycols are impregnated into the injection moulded article as explained above.
  • the impregnated chemicals are further crosslinked off-line or on-line (see example 1) using e.g. UV photopolymerisation.
  • Method to change the haptic appearance of a surface Following the injection moulding or extrusion of any plastic, the article is subjected to the impregnation of compounds mentioned in WO 03/ 068846 A1 or compounds selected from the group of derivatives of styrene, polymers of butadiene or isoprene, or derivatives of fatty acids including multiply unsaturated fatty acids and alcohols and esters, including alcoxylated alcohols.
  • the impregnated chemicals are cross-linked thereafter off-line.
  • the method is especially useful for silicone and other rubbers, and the process may be combined with the initial removal of process oils from the substrate, followed by impregnation.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Plasma & Fusion (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Treatments Of Macromolecular Shaped Articles (AREA)
EP05001442A 2005-01-25 2005-01-25 Procédé et dispositif de traitement d'un article moulé par injection avec un gaz Withdrawn EP1683626A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP05001442A EP1683626A1 (fr) 2005-01-25 2005-01-25 Procédé et dispositif de traitement d'un article moulé par injection avec un gaz
PCT/EP2006/000458 WO2006079477A1 (fr) 2005-01-25 2006-01-19 Procede et appareil permettant de traiter des articles moules par injection avec du gaz

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP05001442A EP1683626A1 (fr) 2005-01-25 2005-01-25 Procédé et dispositif de traitement d'un article moulé par injection avec un gaz

Publications (1)

Publication Number Publication Date
EP1683626A1 true EP1683626A1 (fr) 2006-07-26

Family

ID=34933441

Family Applications (1)

Application Number Title Priority Date Filing Date
EP05001442A Withdrawn EP1683626A1 (fr) 2005-01-25 2005-01-25 Procédé et dispositif de traitement d'un article moulé par injection avec un gaz

Country Status (2)

Country Link
EP (1) EP1683626A1 (fr)
WO (1) WO2006079477A1 (fr)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0204950A2 (fr) * 1985-05-14 1986-12-17 Bayer Ag Procédé pour absorber dans une surface
EP0541230A2 (fr) * 1991-10-07 1993-05-12 Ford Motor Company Limited Procédé pour la fabrication d'un article traité par un plasma
WO1996026059A1 (fr) * 1995-02-22 1996-08-29 Novartis Ag Procede de degagement, d'extraction et de nettoyage d'articles polymeres a l'aide d'un fluide supercritique
JP2000326372A (ja) * 1999-05-21 2000-11-28 Sony Corp ディスク基板の製造装置
WO2003049929A1 (fr) * 2001-11-19 2003-06-19 Jes Tougaard Gram Application de peinture et durcissement de la peinture appliquee sur des elements moules dans un outil equipe d'un element de moule mobile
WO2003068846A1 (fr) * 2002-02-18 2003-08-21 Nkt Research & Innovation A/S Procedes pour traiter des substrats polymeres
JP2004271635A (ja) * 2003-03-05 2004-09-30 Yazaki Corp 導光・光拡散樹脂材料及びその製造方法

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0204950A2 (fr) * 1985-05-14 1986-12-17 Bayer Ag Procédé pour absorber dans une surface
EP0541230A2 (fr) * 1991-10-07 1993-05-12 Ford Motor Company Limited Procédé pour la fabrication d'un article traité par un plasma
WO1996026059A1 (fr) * 1995-02-22 1996-08-29 Novartis Ag Procede de degagement, d'extraction et de nettoyage d'articles polymeres a l'aide d'un fluide supercritique
JP2000326372A (ja) * 1999-05-21 2000-11-28 Sony Corp ディスク基板の製造装置
WO2003049929A1 (fr) * 2001-11-19 2003-06-19 Jes Tougaard Gram Application de peinture et durcissement de la peinture appliquee sur des elements moules dans un outil equipe d'un element de moule mobile
WO2003068846A1 (fr) * 2002-02-18 2003-08-21 Nkt Research & Innovation A/S Procedes pour traiter des substrats polymeres
JP2004271635A (ja) * 2003-03-05 2004-09-30 Yazaki Corp 導光・光拡散樹脂材料及びその製造方法

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 2000, no. 14 5 March 2001 (2001-03-05) *
PATENT ABSTRACTS OF JAPAN vol. 2003, no. 12 5 December 2003 (2003-12-05) *

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